Many oil reservoirs have a relatively low pressure which limits the production. If a new well is going to be arranged in such a reservoir, the well may be supplemented is with a deeply located downhole pump. A deeply located/arranged downhole pump may be post-installed in wells with dryly arranged wellhead, i.e. the wellhead is onshore or dryly on a steady installation, by applying coiled tubing technology to lower and arrange a pump in the production tubing of the well, the coiled tube is used to lower the pump and to contain a power cable. The above mentioned technology is applied today, for example in Yme field of Statoil which contains a steady platform with dryly arranged wellhead.
For existing wells having low pressure and subsea arranged wellhead, no simple solution to increase the well production by installing a deeply arranged downhole pump in the production tubing exists today. Such installation would today require that the tubing is pulled out and the well being recompleted. There is a need for a simple solution to increase the production from an existing subsea arranged oil production well. By simple solution it is here meant the arrangement of a downhole pump deep down in the tubing without pulling out the tubing and to recomplete the well.
An existing oil producing well having low pressure would typically be in a final stage of its production lifetime, in which the pressure in the reservoir has fallen to a low level that limits the production. The well would typically be equipped with existing hydraulically operated systems, included a hydraulically operated downhole valve in the tubing close to the upper part of the well. One object with the present invention is to provide a method to modify a well of the above mentioned type, together with a thus modified well, to render possible the installation of a downhole pump without having to pull out the tubing and to recomplete the well.